


Complexity Theory

by eve11



Category: Doctor Who, Doctor Who (2005), Numb3rs
Genre: Crossover, M/M, One Shot
Language: English
Status: Completed
Published: 2011-06-12
Updated: 2011-06-12
Packaged: 2017-10-20 08:54:45
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 831
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/210978
Author URL: https://archiveofourown.org/users/eve11/pseuds/eve11
Summary: <blockquote class="userstuff">
              <p>They don't teach you.</p>
            </blockquote>





	Complexity Theory

If you asked Charlie Eppes why he hated teaching, he'd give you the standard reasons--the under-appreciative, bored students, the task of imparting _understanding_ as opposed to rote memorization that was remarkably like trying to sculpt with honey, or finally the lack of gravitas a young post-doc, barely older than his students, needed for controlling a classroom--a phenomenon that Larry, in a fit of social perception, had deemed the "beard and pot-belly effect."

Sure, he'd say all that. But what Charlie really hated were know-it-alls.

"All I'm saying," the foreigner in the incongruous suit and trainers imparted from the back, "is that when you fail to account for complexity in a predictive model, you overgeneralize."

He wasn't sure which he hated more--the ones who didn't really know anything, or the ones who did. He cleared his throat. "If you'll notice the penalty term in the selection criterion--"

"What, that silly linear approximation? Think that's enough, do you? That you can define the extent of what you _don't know_ with a simple Taylor series? Come on."

Time seemed to be slowing down. He was losing the class, measured in shifty glances from the eyes of the other students, in each pen stopped mid-notes to gawk in morbid fascination at this contest, tacitly saying, _you'd better come up with something or I'll have no reason to listen to you ever again._

He took a breath. "Kolmogorov defined complexity--"

" _Andrey?_ Please, the man was a chore, and an engineer. You may be an applied mathematician, but that's no reason to start slumming."

Charlie stared at the man. The student, gate-crasher that he was, was obviously smart enough to do the math for himself. "The theory's sound," he said dismissively. "I don't know what else you want to hear."

The man stood, twirling a pencil. "Explain to me _why_ you can be so sure of yourself."

Charlie laughed. Genuinely laughed, and at that moment he felt an easy confidence overtake the room.

"Can't you see?" he said. "It's all there on the board."

The troublemaker left without another word, and the tension in the classroom melted away. Charlie locked eyes with each of his students and prepared another salvo of equations. Perhaps this lecture would be salvageable after all.

**

It was all there on the board, he thought. All wrapped up elegantly and smoothly. Only this time, it wasn't.

All this time, helping Don had been like a game, and he'd never made a mistake, not once. Until now. It was a routine case ( _kidnapping, extortion, when had that become routine?_ ), a routine application of proportional hazards, and then the whole thing blew up in his face. So here he was, sitting at an upscale bar, alone with a bowl of cashews and his fourth scotch, trying not to think of two little girls who'd never see their parents again.

When he stumbled off the chair and directly into a tall brown blur that knocked him unceremoniously to his knees, his memory, whose preternatural gift for pattern-matching had driven Don to never, ever play him at cards from the age of five onwards, went into overdrive.

"Six years, same suit," he mumbled up at the man.

"I beg your pardon?" the foreigner said, offering a hand. "Do I know you?"

Same voice, too. Charlie stood, weaving dangerously. "Six years later, same suit, same shoes," he clarified. "What are the odds?"

"With me? Pretty good, actually." The man wrapped an arm around him, uncommonly strong for such a thin frame. For the briefest moment, Charlie felt the impossibility of this force, extrapolated the limits of human strength versus size and decided he was a victim of spurious alcohol-induced inference. Because for a moment, he felt as if he'd never fall again.

"Hello," the stranger said. "I'm--"

"Shut up," Charlie answered. "You were right, that's what."

The man wrinkled his brow. "I . . . was?"

"When you said--" Charlie started, and the stranger's eyes widened in sudden comprehension as he said, "No, wait, don't tell me--"

Their fingers brushed. There was a flash in Charlie's mind-- an understanding so deep there was no calculus for it--a language so precise that every word spoken was brand new and never used again. And over all of it was a loss crystallized--mapped and metrized and still terrible, inevitable.

Charlie shuddered, and the thought was gone. But they had both felt it; a commonality of betrayal, of loss normalized against lifetime. It seized them so wholly, so oddly, that the intimacy that followed paled in comparison--a wooden box and an impossible room in an alleyway, skin on cool skin, hushed kisses in the dark, hands traveling the contours of each other like crude approximation algorithms over an incomplete, inadequate space.

"They don't teach you," Charlie whispered in the stillness afterward. "I wish I'd understood."

His companion frowned, eyes flicking downward and a shadow of worry crossing his brow in the dimness. "Understood what?"

"That numbers can't solve everything."


End file.
